A STREET IS NOT A HOME: Solving America's Homeless Dilemma by Robert C. Coates (Prometheus Books: $14.95; 356 pp.). The federal government seemed so colossally inept at helping the homeless in the '80s that most of us tend to be cynical about solutions. San Diego Municipal Court Judge Robert Coates undoubtedly felt some of that frustration when trying to develop social services in his own community (at one point he writes cryptically that "Those in power . . . were repulsive to us"), but he lets nary a downbeat note sound in his lucid descriptions of how ordinary citizens can initiate promising community projects. Coates' hard sell is certainly inspiring, but he achieves his upbeat tone by glossing over the fact that the small-scale projects described here are unlikely to help the majority of this nation's 3 million homeless.